Category: Laboratory Research
Effect of Pretreatment Modes on the Adhesion to a Composite CAD/CAM Block
Thao Phoung Danga | Tony Paul Loreya | Renan Bellia | Ulrich Lohbauera | José Zorzina* (jose.zorzin@fau.de)
aOperative Dentistry, University Hospital Erlangen, Erlangen, Germany
Objective: The study aimed to evaluate the influence of different pretreatment modes on the adhesion potential of a luting resin to a composite CAD/CAM block.
Methods: 180 rods (25x4x3mm, height x length x width) were prepared from composite CAD/CAM blocks (Cerasmart 270, GC). A chevron-notch was cut at the middle of the rods with a cutting disc. The notch was split into two matching halves with a thinner cutting disc.
The corresponding halves were divided into six groups and pretreated as follows:
-Group 1 – airborne particle abrasion with 35 μm alumina and silane (EspeSIL, 3M),
-Group 2 - airborne particle abrasion with 35 μm alumina and multi primer (Monobond Plus, Ivoclar),
-Group 3 - hydrofluoric acid etching (VITA Ceramic Etch, VITA) and silane (EspeSIL),
-Group 4 - hydrofluoric acid etching (VITA Ceramic Etch) and multi primer (Monobond Plus),
-Group 5 - silicatization (CoJet, 3M) and silane (EspeSIL),
-Group 6 - silicatization (CoJet) and multi primer (Monobond Plus).
The pretreated halves were luted with a resin (RelyX Universal, 3M) and light cured from all sides (20s, 1200mW/cm^2, Bluephase 20i, Ivoclar), resulting in 30 samples per group. All samples were stored in artificial saliva at 37°C before KIc chevron-notch-beam fracture toughness measurements. Half of the samples from each group (n=15) were measured after 24 h, and the other half (n=15) after 60 d.
Results: After 24 h the Tukey-HSD post hoc test showed that only group 3 (n=9, 0.68±0.1 MPam^1/2) had significantly lower KIc compared to all other groups (p<.05). After 60 d of storage, group 3 (n=10, 0.36±0.06 MPam^1/2) had the significantly overall lowest KIc (p<.05), and group 5 had the significantly highest KIc (n = 9, 1.08±0.13 MPam^1/2, p<.05).
Conclusion: Within the limitations of this study, the silicatization and silanization of the composite CAD/CAM block lead to a higher long-term adhesion in comparison to other pretreatments.
Funding/Conflict of Interest: None
Keywords: adhesion, fracture toughness, CAD/CAM composite, airborne particle abrasion, hydrofluoric acid etching, multi-primer, silane, silicatization
